UKHSA weekly winter virus statistics for the 2026/27 season show norovirus activity remains low and within expected levels. Laboratory reports for weeks 39 and 40 of 2026 were 9.8% below the 5-season average, covering 21 September 2026 to 4 October 2026.
The same bulletin says rotavirus activity was 13.9% higher than the 5-season average over that two-week period, but still within expected levels. That leaves norovirus as the clearer sign of a quieter-than-average stretch, even though both viruses are being tracked in the same weekly surveillance update.
UKHSA bulletin for 2026/27
The bulletin brings together the latest surveillance data and public health advice for flu, COVID-19, Respiratory Syncytial Virus and other viruses. Its weekly format matters because it shows whether current activity is moving inside or outside the seasonal range, rather than relying on a single point in time.
For norovirus, UKHSA said the number of laboratory reports in weeks 39 and 40 was lower than the 5-season average for the same two-week period. In practical terms, that means the latest count sits beneath the benchmark UKHSA uses to compare this point in the season with recent years.
HNORS outbreak reports
Since the start of the 2025/2026 season, the number of norovirus outbreaks reported to HNORS has been 19.2% lower than the 5-season average. During the 2025/2026 season to date, 87.2% of samples characterised were norovirus genogroup 2, and GII.4 was the most frequent genotype at 25.6%.
Those figures help show not just how much norovirus is circulating, but which form is showing up most often in the samples that have been characterised. The breakdown gives a second check on the laboratory trend and shows that the current picture is being watched at both outbreak and sample level.
Norovirus and dehydration
Norovirus symptoms include nausea, vomiting and diarrhoea, and can also include a high temperature, abdominal pain and aching limbs. UKHSA says infection can cause dehydration, which is the main practical risk for young children and older or immunocompromised people.
For readers, the immediate takeaway is straightforward: the latest UKHSA weekly winter virus statistics do not show norovirus activity running above its expected range. Rotavirus has risen above its 5-season average for the same two-week period, but UKHSA still places it within expected levels, so the next weekly bulletin will show whether that gap narrows or widens.
